1. Field of Invention
This invention relates to a bumper assembly and in particular an assembly for use on motor vehicles in particular cars and vans.
2. Background of Invention
It is known that automobile bumpers should be designed to withstand small impact forces without damage, or at least minimum damage, occurring at low speeds. Typical low speeds occur during vehicle manoeuvering whilst parking. However, modern bumper assemblies must also be capable of offering protection to pedestrians when impacted by a slow moving vehicle.
A known bumper assembly which is claimed to alleviate pedestrian injury is disclosed in GB-A-2322 602 which provides a bumper assembly which comprises a plastic shell mounted on a support rail with the space between the shell and rail being substantially foam filled with different density foams. In one embodiment the upper portion of shell is hollow and collapses on initial impact onto the foam filling which creates an inclined face which is intended to guide a pedestrian onto the bonnet where it is believed that the pedestrian is in less danger of injury.
However many vehicles have a vehicle registration plate mounted on the front bumper assembly and a pedestrian friendly bumper assembly must also protect against injury from the number plate.
The present invention provides an improved vehicle bumper system with a pedestrian friendly vehicle registration plate assembly.
According to the present invention there is provided a bumper assembly comprising a support which is covered by a resilient shell part, the lower portion of the shell being backed by foam material mounted on the support, with the upper portion of the shell being unsupported having clearance therebehind, and a registration plate plinth having an upright limb to which the number plate is secured and which is attached to the shell with the lower portion of said limb supportable on said foam and the upper portion of said limb being supportable only by the shell.
The shell is preferably made from a polyolefinic material preferably from a polypropylene based material which may include EPDM rubber. The foam is preferably a polyurethane foam which in the area behind the plinth may have a density 60-80 gms per liter.
When a vehicle registration plate is mounted on the plinth and in the event of a collision with a pedestrian, since only the lower portion of the plinth limb is supported on the foam and the upper portion is supported on the deformable and collapsible shell, the plinth can move into the shell and tilt or rotate absorbing impact energy and supporting the lower leg of the pedestrian.
Preferably number plate plinth further comprises at least one reawardly extending portion which is attached to a substantially horizontal portion of the shell. The rearwardly extending portion(s) may be attached to the shell by a load sensitive device which allows the rearwardly extending portion to move rearwards relative to the shell under a predetermined minimum load. The upright limb comprises a plate having a top edge and the rearward portion(s) extend from a top edge substantially normal of the plate.
The plinth is attached to the shell by fastening members extending through the upright limp.
The bumper assembly may Include a hoop-like support means having a central aperture surrounded by an upper beam and a lower beam connected by outer side portions, and said support comprises the lower beam.
Any number plate on the plinth may extend downwardly beyond the plinth such that the upper portion of the number plate above the foam is not less than 50% of the overall height of the plate.
Preferably the upper beam is set backwards from the front surface of the foam on the lower beam such that a line connecting points on said upper beam and front surface makes an angle of inclination to the vertical of at least 12 degrees of arc and the plinth is mounted so that its rearwards extensions(s) are secured to part of the surrounding the aperture and the plate can tilt to at least said inclination.
The open centre of the support allows for a open centred bumper assembly which facilitates vehicle engine cooling.
The hoop-like support is preferably formed from a suitable thermoplastics plastics materials and is preferably formed from a polycarbonate based material, for example Xenoy (TM) available from General Electric.
The support and foam backing provides a support for said lower leg which is located in use at a height of about 260-270 mm above ground.